This invention relates to a device for the transverse scanning optical reading of information carriers or media, more particularly of rectangular planar carriers in which data are stored, such as cards carrying an opaque or transparent band containing coded data, e.g. analogically coded, or dot or bar coded, and the like.
Several and different devices are known, generally called readers or scanners, which allow for the extraction of data from carriers carrying coded information, through magnetic, capacitive, optical or mechanical phenomena.
More particularly, the optical readers are considered with interest in view of the high resolution, non intrusiveness and good safety prospects of the optical reading.
The resolution of such devices is a function of the overlapping degree which can be obtained between the picture elements or pixels of the carrier to be read (or the corresponding focused picture), and the individual sensors or elemental sensors associated with the picture elements.
The known devices have, among the others, the drawback of being highly sensible to an incorrect carrier introduction, or to its uneveness and being asymmetric. This is a strong limit to the spreading of such devices since the reader has to be reliable and to accomplish its task also under non ideal conditions, e.g. with the carrier being inserted slightly inclined with respect to the reader axis, with worn carriers, or carriers having a width which is not constant, etc.